We discuss how tight-binding band-structure calculations with a chirality- and diameter-dependent nearest-neighbor hopping integral and an energy independent offset parameter may be used to correlate the geometric structure of single-wall carbon nanotubes (SWNTs) with well resolved features in the UV-VIS-NIR absorption spectra . The assignment of (n,m) indices to interband transitions in specific tube types can support a quantitative analysis of absorption spectra which may eventually be used for rapid screening and optimization of sample composition during SWNT synthesis.